Generalized geometric random channel modeling method for indoor optical wireless communications

Abstract

The application discloses a general geometric random channel modeling method for indoor optical wireless communication, and belongs to the field of wireless communication channel modeling. The method comprises the following steps: setting scene layout and frequency band related parameters; generating object reflection cluster birth-death process matrix and random numbers for controlling blocking effect and propagation component classification; initializing scattering clusters and scattering bodies in the clusters; updating and calculating model parameters changing with space and time; calculating light source radiation intensity, object reflection and particle scattering power distribution, and equivalent reflection coefficient; calculating sub-channel impulse response, judging whether the propagation component exists or not, and generating final channel impulse response. The general indoor optical wireless communication geometric random channel modeling method can depict common characteristics of optical wireless frequency bands and unique characteristics of infrared light, visible light and ultraviolet light frequency bands. Through setting corresponding parameters, the established model can support different frequency bands and can be flexibly used for simulation and performance evaluation of a 6G indoor optical wireless communication system.

Description

Technical Field

[0001] This application relates to the field of wireless communication channel modeling technology, and in particular to a general geometric random channel modeling method for indoor optical wireless communication. Background Technology

[0002] With the widespread adoption of smart terminals and the rapid development of the information age, people's demands for communication services are constantly increasing. Wireless communication has evolved from the first generation (1G) to the fifth generation (5G), with increasingly higher frequency bands, increased bandwidth, and rapidly growing peak data rates. To meet the demands of continuously growing data traffic and connection numbers, and to alleviate the saturation crisis of the radio frequency spectrum, optical wireless communication has attracted widespread attention due to its unlicensed ultra-wide spectrum, high data security, low cost, low power consumption, and resistance to electromagnetic interference. The optical wireless band includes infrared, visible, and ultraviolet light, with wavelengths ranging from approximately 200nm to 3000nm and frequencies from approximately 100THz to 1500THz. Its applications include high-speed indoor data communication, outdoor vehicle-to-vehicle communication, underwater communication, and aerial communication. Compared to traditional radio frequency bands, optical wireless communication channels exhibit propagation characteristics such as no small-scale fading, negligible Doppler, significant influence from the directionality of the transmitting and receiving ends, susceptibility to obstruction, atmospheric absorption and scattering, diffuse reflection, and wavelength dependence of the reflection coefficient. These characteristics present challenges to the design, analysis, and application of optical wireless communication systems. The analysis and modeling of optical wireless communication channel characteristics are the foundation for system design, performance evaluation, optimization and deployment.

[0003] Currently, infrared and visible light communication are mostly used in indoor scenarios. In recent studies, ultraviolet light has also been explored for indoor communication. The modeling of optical wireless communication channels in typical indoor scenarios has attracted considerable attention from researchers, resulting in the proposal of numerous indoor optical wireless channel models, which can be categorized into deterministic and stochastic channel models. Typical deterministic optical wireless channel models include recursive channel models, ray tracing models based on Zemax, and single-scattering theory models. These models offer high accuracy; however, they suffer from high computational complexity and lack universality. Stochastic channel models include the Geometry-Based Stochastic Model (GBSM) and non-geometric stochastic channel models. GBSM abstracts the environment as a scattering body, allowing channel information to be obtained through simple ray tracing. This method boasts high universality and has been adopted by several 5G standardized channel models.

[0004] In the era of sixth-generation wireless communication (6G), various communication technologies will continue to develop and show a trend of converged applications. Proposing a universal channel model using a unified model framework is beneficial for promoting the standardization of 6G channel models and the research of 6G communication systems. It is worth noting that current existing optical wireless communication channel models mostly focus on a single frequency band, and a few universal models only support outdoor non-line-of-sight scattering communication scenarios and cannot be used in indoor scenarios. To date, no universal channel model supporting all optical bands for indoor scenarios has been proposed. Summary of the Invention

[0005] This application provides a general geometric random channel modeling method for indoor optical wireless communication. It considers typical indoor communication scenarios, integrates the common propagation characteristics of optical wireless communication frequency bands with the unique propagation characteristics of infrared, visible, and ultraviolet light, and proposes a three-dimensional general optical wireless communication geometric random channel model for indoor use, providing a research foundation for the design and development of 6G optical wireless communication systems.

[0006] This application provides a general geometric random channel modeling method for indoor optical wireless communication, including the following steps:

[0007] Step S1: Establish an indoor optical wireless communication channel simulation scenario and set the simulation scenario layout and frequency band parameters;

[0008] Step S2: Generate the object reflection cluster birth and death process matrix of the transmitting end array, the random number matrix controlling the existence of the direct component, and the random number matrix classifying the propagation components;

[0009] Step S3: Initialize the object reflection cluster, particle scattering cluster, and intra-cluster scatterers;

[0010] Step S4: Update the model parameters that vary with space and time;

[0011] Step S5: Calculate the light source radiation intensity, object reflected power distribution, particle scattered power distribution, and equivalent reflection coefficient related to wavelength range;

[0012] Step S6: Calculate the impulse response of each sub-channel, determine whether the direct component of the sub-channel exists and whether the indirect component of the object reflection exists, and obtain the final channel impulse response.

[0013] In one embodiment of this application, step S1 further includes:

[0014] Step S101: Establish an indoor optical wireless communication channel simulation scenario. The indoor optical wireless communication channel simulation scenario includes an LED array as the transmitter and a photodetector as the receiver. Define the ray from the first row and first column of the LED unit at the transmitter to the receiver as the x-axis, and the plane perpendicular to it as the yoz plane to establish a global coordinate system.

[0015] Step S102: Set the physical environment parameters of the simulation scene layout, including transmitter parameters, receiver parameters, distance parameters, and blocking effect parameters;

[0016] Step S103: Set frequency band parameters, including the proportion η of single-cluster propagation. SB The probability p that the propagation component is scattered by particles in the environment particle The proportion α of diffuse reflection of light signals on materials in the environment n Extended parameter σ of the object reflection cluster RE Extended parameter σ of particle scattering cluster PS Particle extinction coefficient k e Rayleigh scattering coefficient k of particles sr Particle Mie scattering coefficient k sm .

[0017] In one embodiment of this application, step S102 further includes:

[0018] Step S1021: Set the transmitter parameters, including the direction parameters of the LED array and the number M of LED units in the horizontal direction of the LED array. I and unit spacing The number of LED units M in the vertical direction of the LED array J and unit spacing The orientation parameters of the LED array include the azimuth angle of the LED array facet in the horizontal direction. With pitch angle The azimuth angle of the LED array in the vertical direction With pitch angle

[0019] Step S1022: Set the receiver parameters, including the azimuth angle of the receiver normal. With pitch angle Area A of the receiving end R The visible field of view Ψ of the receiving end FoV , Translational motion direction angle of the receiving end With pitch angle and the magnitude of the velocity v R (t) Rotational azimuth velocity of the receiving end With pitch angular velocity

[0020] Step S1023: Set distance parameters, including the first row and first column of LED units L of the LED array. 11 Distance D from the receiver 11 ;

[0021] Step S1024: Set the blocking effect parameters, including the probability p that the line-of-sight component is blocked. blockage .

[0022] In one embodiment of this application, step S2 further includes:

[0023] Step S201, generating the object reflection cluster birth and death process matrix of the transmitting end array, specifically including:

[0024] Step S2011, calculate the LED unit L 11 The number of clusters N observed at the initial moment c0 The expression is:

[0025]

[0026] Where, λ B With λ D These represent the birth rate and death rate of the cluster, respectively.

[0027] Step S2012, using the LED unit L 11 Based on this, the first column of LED units is generated. For the visibility matrix of clusters, where column evolution is performed in the horizontal direction, the clusters are at a spacing of The probability of survival at a distance of:

[0028]

[0029] in, Array-related factors are specific to certain scenarios;

[0030] The number of newly generated clusters follows a Poisson distribution with a mean of:

[0031]

[0032] Step S2013, using the first column of LED units generated in step S2012 Based on this, a visibility matrix for each column of LED units to the cluster is generated, wherein column evolution is performed in the vertical direction, and the clusters are spaced at intervals of [missing information]. The probability of survival at a distance of:

[0033]

[0034] The number of newly generated clusters follows a Poisson distribution with a mean of:

[0035]

[0036] Step S2014: Generate the final object reflection cluster birth and death process matrix of the transmitting end array, which is a matrix of size M. I ×M J ×N c，total The matrix, where N is the total number of object reflection clusters. c，total equals N c0 The sum of the number of newly generated clusters;

[0037] Step S202: Calculate the probability p of the direct component existing. LoS =(1-p blockage )·(1-p particle A 0 / 1 random number matrix of size M is generated based on the probability of the presence of the direct component, controlling the presence or absence of the direct component. I ×M J According to p particle Generate M n A random number (M) is used to classify whether the propagated component after reflection from an object is scattered again before reaching the receiver. n This represents the number of scatterers within the object's reflection cluster.

[0038] In one embodiment of this application, step S3 further includes:

[0039] Step S301: Randomly generate the initial position of the object reflection cluster. The initial position of the cluster is determined by the azimuth angle, pitch angle, and distance parameters, specifically including:

[0040] Step S3011, randomly generate N c，total The angular parameters of each object's reflection cluster are all modeled as following a tangled normal distribution, generating N. c，total ×(1-η SB ) Angular parameters of the object reflection clusters at the receiving end;

[0041] Step S3012: Randomly generate the initial distance L of the object reflection cluster to the LED unit. 11 distance and And it follows a non-negative exponential distribution;

[0042] Step S302: Calculate the equivalent normal direction and equivalent specular reflection direction for each object reflection cluster based on geometric relationships; for a single object reflection, the equivalent normal points from the cluster center to L. 11 The ray reaching the receiving end and perpendicular to the ray, the equivalent specular reflection direction vector is perpendicular to the cluster center, L 11 And the receiving end is in the same plane, and the angle between it and the equivalent normal is equal to the distance from the cluster center to L. 11The angle between the vector and the equivalent normal; in the case of double object reflection, the equivalent normal of the cluster on the emitting end side points from the cluster center to L. 11 The ray reaching the cluster at the receiving end and perpendicular to the ray, its equivalent specular reflection direction vector is perpendicular to the cluster center, L 11 The clusters on the receiving end side are located in the same plane, and the angle between the cluster center and the equivalent normal is equal to the angle from the cluster center to L. 11 The angle between the vector and the equivalent normal, the equivalent normal of the receiver-side cluster points from the cluster center to the ray from the transmitter-side cluster to the receiver and is perpendicular to the ray, its equivalent mirror reflection direction vector is in the same plane as the cluster center, the transmitter-side cluster and Rx, and the angle between it and the equivalent normal is equal to the angle between the vector from the cluster center to the transmitter-side cluster and the equivalent normal.

[0043] Step S303: Generate a particle scattering cluster that characterizes the particle scattering effect of ultraviolet light signal on the receiving end side. The azimuth and elevation angles of the ray from the receiving end to the center of the particle scattering cluster are consistent with the normal direction of the receiving end. The distance between the center of the particle scattering cluster and the receiving end is set to a constant.

[0044] Step S304: Randomly generate the coordinates of each cluster scatterer in the global coordinate system, specifically including:

[0045] Step S3041: Randomly generate the coordinates [x′, y′, z′] of the scatterer within each cluster in a local coordinate system with the cluster center as the origin. T Furthermore, it follows a three-dimensional ellipsoidal Gaussian distribution, expressed as:

[0046]

[0047] Where, σ DS σ AS σ ES These represent intra-cluster time delay spread, angle spread, and pitch spread, respectively. When generating object reflection clusters and particle scattering clusters, different cluster spread parameters are substituted in.

[0048] Step S3042: Obtain the coordinates [x, y, z] of each scatterer in the global coordinate system through coordinate transformation. T The expression is:

[0049]

[0050] in, These represent the average distance, azimuth, and elevation angle of a cluster, respectively.

[0051] In one embodiment of this application, step S4 further includes:

[0052] Step S401: Based on the geometric relationship and the set motion velocity of the object reflection cluster, the motion and rotation velocity of the receiver, update the coordinates of the scatterer and the receiver in the global coordinate system at each moment, and calculate L. ij Coordinates in the global coordinate system;

[0053] Step S402, update and calculate the angle parameters of each propagation ray in the local coordinate system of each LED unit. Specific steps include:

[0054] Step S4021, take the cell L containing the i-th row and j-th column of the LED array as an example. ij With the origin as the reference point, the normal direction of the LED array is x′. ij The axis and the vertical direction of the LED array are y′. ij The axis and the horizontal direction of the LED array are z′ ij Axis establishes LED unit L ij The local coordinate system;

[0055] Step S4022: The Cartesian coordinates of each scatterer obtained in step S3042 in the global coordinate system are first transformed by rotation to obtain the LED unit L. 11 The Cartesian coordinates of the local coordinate system are then transformed to obtain the LED element L. ij The Cartesian coordinates of the local coordinate system are used to finally determine the LED element L. ij Converting the Cartesian coordinates of the local coordinate system to spherical coordinates, we obtain the coordinates of each propagating ray in the LED unit L. ij Pitch departure angle and azimuth departure angle in the local coordinate system, including the direct path in L ij Pitch departure angle in local coordinate system Angle of departure from azimuth From L ij The ray reaching the q-th scatterer within the particle scattering cluster at L ij Pitch departure angle in local coordinate system Angle of departure from azimuth From L ij The ray from the m1 (m2)th scatterer within the nth object reflection cluster at the emitting end is at L ij Pitch departure angle in local coordinate system Angle of departure from azimuth

[0056] Step S403 involves updating and calculating the angle parameters of each propagating ray based on the updated global coordinates of each scatterer and receiver in step S401. Specific steps include:

[0057] Step S4031: Based on the propagation component classification 0 / 1 random number generated in step S202, determine whether the rays in the single object reflection cluster reach the receiving end only after a single reflection.

[0058] Step S4032: Obtain the normalized transmission vector according to the coordinate method, including L ij Normalized direction vector to the receiver L ij Normalized direction vector to the q-th scatterer within the particle scattering cluster Normalized direction vector from the q-th scatterer in the particle scattering cluster to the receiver L ij The normalized direction vector of the m1(m2)th scatterer within the nth object reflection cluster at the transmitter side The normalized direction vector from the m1(m2)th scatterer within the nth object reflection cluster at the transmitter to the receiver. The normalized direction vector from the m1-th scatterer within the nth object reflection cluster at the transmitter side to the m1-th scatterer within the nth object reflection cluster at the receiver side. The normalized direction vector from the m2-th scatterer within the n-th object reflection cluster at the emitter side to the q-th scatterer within the particle scattering cluster.

[0059] Step S4033: Update the angle parameters of each propagation component according to the law of cosines, including... Angle with the direction of the receiver's normal and The included angle Angle with the direction of the receiver's normal The angle between the equivalent normal direction of the nth object reflection cluster on the transmitter side and the target surface. The angle between the equivalent normal direction and the equivalent specular reflection direction of the nth object reflection cluster on the transmitter side and Angle with the direction of the receiver's normal The angle between the equivalent normal direction and the equivalent specular reflection direction of the nth object reflection cluster on the transmitter side and and The included angle

[0060] Step S404, based on the updated scatterers and L in step S401 ij The global coordinates of the receiving end and the coordinate method are used to update and calculate the propagation distance parameters of each propagating ray at each moment, including L. ij Distance D to the receiver ij (t), L ij Distance to the q-th scatterer within the particle scattering cluster The distance from the q-th scatterer within the particle scattering cluster to the receiver. L ij Distance to the m1(m2)th scatterer within the nth object reflection cluster on the transmitter side The distance from the m1 (m2)th scatterer within the nth object reflection cluster on the transmitter side to the receiver. The distance from the m1-th scatterer within the n-th object reflection cluster on the transmitter side to the m1-th scatterer within the n-th object reflection cluster on the receiver side. The distance from the m2-th scatterer within the n-th object reflection cluster on the emitter side to the q-th scatterer within the particle scattering cluster.

[0061] In one embodiment of this application, step S5 further includes:

[0062] Step S501: Calculate the light source radiation intensity in the direction corresponding to the propagating ray, expressed as:

[0063]

[0064] Where α is the mode number of the Lambertian radiation mode; Substitute the angle parameters calculated in step S4022 into the above formula to calculate the light source radiation intensity corresponding to each propagation component.

[0065] Step S502: Calculate the power distribution of the propagating ray after reflection by the object based on Phong's reflection model. The expression is:

[0066]

[0067] Where, m sn Here is the directional parameter of the specular reflection component; Substitute the angle parameter between the propagation ray and the equivalent normal of the object reflection cluster and the equivalent specular reflection direction calculated in step S4033 into the above formula to calculate the power radiated per unit solid angle in the propagation direction of the propagation component after object reflection.

[0068] Step S503: Calculate the power distribution of the propagating ray after particle scattering based on the particle scattering phase function. The expression is:

[0069]

[0070] Where, k s The scattering coefficient is equal to the Rayleigh scattering coefficient k of the particle. sr With particle Mie scattering coefficient k sm The sum of P r (θ PS ) and P m (θ PS) are the Rayleigh scattering phase function and the Mie scattering phase function, respectively, where P r (θ PS The expression for ) is:

[0071]

[0072] Wherein, γ is a parameter of the Rayleigh scattering model, which is determined by the depolarization factor;

[0073] P m (θ PS The expression for ) is:

[0074]

[0075] Where g and f are Mie scattering model parameters related to the light wavelength; the angle parameters calculated in step S4033 are... and Substituting into the particle scattering phase function expression, the power radiated per unit solid angle in the propagation direction of the propagation component after particle scattering is calculated respectively.

[0076] Step S504: Calculate the equivalent reflection coefficient related to the wavelength range, expressed as:

[0077]

[0078] Where, Φ ij (λ) represents the LED unit L ij Radiative power spectral density as a function of wavelength, ρ n (λ) represents the reflectivity of the nth object's reflective cluster as a function of wavelength, and [λ1, λ2] represents the wavelength range of the color of the light emitted by the LED.

[0079] In one embodiment of this application, step S6 further includes:

[0080] Step S601, calculate the channel impulse response of the direct propagation component, specifically including:

[0081] Step S6011: Calculate the power of the direct propagation component of the ray, expressed as:

[0082]

[0083] Among them, in the infrared and visible light frequency bands of indoor scenes, k is set e When = 0, the model simplifies to a model that supports both infrared and visible light, and the particle extinction decay is 1;

[0084] Step S6012, calculate the propagation delay of the direct propagation component, the expression is:

[0085]

[0086] Among them, c l The speed of light;

[0087] Step S6013: Generate the channel impulse response of the direct component in each sub-channel based on the parameters calculated in steps S6011 and S6012, expressed as:

[0088]

[0089] Step S602, calculate the channel impulse response of the non-direct propagation component, specifically including:

[0090] Step S6021, calculate from L ij The power of the propagating component of the emitted ray that reaches the receiver only after being scattered by particles is expressed as:

[0091]

[0092] Among them, V q，eff Let V be the equivalent volume of each scatterer in the particle scattering cluster, and V be the equivalent volume of the particle scattering cluster. c，eff Correlation, calculated as V q，eff =V c，eff / Q PS Q PS G(ψ) represents the number of scatterers in the particle scattering cluster. R ) and T(ψ R ) represent the gain of the optical focusing lens and the gain of the optical filter, respectively, V(ψ) R ) is the visible field function, V(ψ) R The expression for ) is:

[0093]

[0094] Step S6022, calculate from L ij The time delay of the propagating component of the emitted ray that reaches the receiver only after being scattered by particles is expressed as:

[0095]

[0096] Step S6023, calculate from L ij The power of the propagating component of the emitted ray that reaches the receiver only after being reflected by an object, in the case of a single reflection, is expressed as:

[0097]

[0098] In the case of double object reflection, the channel is characterized by two clusters located at the transmitting and receiving ends respectively. Compared with the case of single reflection, the calculation of ray power increases the power loss from the scatterer at the transmitting end to the scatterer at the receiving end.

[0099] Step S6024: Calculate from L ij The power of the propagating component of the emitted ray that reaches the receiver only after being reflected by an object, in the case of a single reflection, is expressed as:

[0100]

[0101] In the case of double reflection, the expression is:

[0102]

[0103] Step S6025, calculate from L ij The power of the propagating component of the emitted ray, after being reflected by an object and scattered by particles again, is expressed as:

[0104]

[0105] Wherein, the signal passes through a random M within each object reflection cluster. n ·p particle Each scatterer undergoes particle scattering again. Based on the propagation component classification 0 / 1 random number generated in step S202, it is determined whether the rays in the object reflection cluster have undergone single object reflection and particle scattering again to reach the receiving end.

[0106] Step S6026, calculate from L ij The propagation time delay of the component that is reflected by an object and then scattered by particles is expressed as:

[0107]

[0108] Step S6027: Generate the channel impulse response of the direct component in each sub-channel based on the parameters calculated in steps S6021 to S6026, the expression of which is:

[0109]

[0110] Where, N ij (t) represents the LED unit L ij The number of clusters of the sub-channels at time t at the receiving end; in indoor scenes, setting p in the infrared and visible light frequency bands. particle =0, k e When =0, the model is simplified to a model that supports infrared and visible light, with only the non-direct component that reaches the receiver after being reflected by the object, and the particle extinction attenuation of the non-direct component calculated in step S6023 is 1.

[0111] Step S603: Determine whether the non-direct component corresponding to the object reflection cluster exists based on the birth and death matrix generated in step S201, and set the contribution of the invisible link to the channel impulse response to zero.

[0112] Step S604: Determine whether the direct component exists in each sub-channel based on the random number matrix generated in step S202 that controls the existence of the direct component, and obtain the final channel impulse response.

[0113] The general geometric random channel modeling method for indoor optical wireless communication in this application integrates the common characteristics of optical wireless communication frequency bands in typical indoor scenarios with the typical characteristics of infrared, visible, and ultraviolet light frequency bands. By setting the corresponding parameters, the established model can be simplified into an optical wireless channel model for the corresponding band, which can be flexibly used for simulation and performance evaluation of 6G optical wireless communication systems.

[0114] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0115] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0116] Figure 1 This is a flowchart illustrating a general geometric random channel modeling method for indoor optical wireless communication according to an embodiment of this application;

[0117] Figure 2 This is a schematic diagram of a geometric random channel model for indoor three-dimensional universal optical wireless communication provided according to an embodiment of this application. Detailed Implementation

[0118] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0119] Figure 1 This is a flowchart of a general geometric random channel modeling method for indoor optical wireless communication provided according to an embodiment of this application.

[0120] like Figure 1 As shown, this general geometric random channel modeling method for indoor optical wireless communication includes the following steps:

[0121] Step S1: Establish an indoor optical wireless communication channel simulation scenario and set the simulation scenario layout and frequency band parameters.

[0122] Specifically, in this embodiment, step S1 includes:

[0123] Step S101: Establish an indoor optical wireless communication channel simulation scenario, including an LED array as the transmitter and a photodetector as the receiver. Define the ray from the first row and first column of LED units at the transmitter to the receiver as the x-axis, and the plane perpendicular to it as the yoz plane to establish a global coordinate system.

[0124] Step S102: Set the physical environment parameters of the scene layout, including transmitter parameters, receiver parameters, distance parameters, and obstruction effect parameters:

[0125] Step S1021: Set the transmitter parameters, including the direction parameters of the LED array and the number M of LED units in the horizontal direction of the LED array. I and unit spacing The number of LED units M in the vertical direction of the LED array J and unit spacing The orientation parameters of the LED array include the azimuth angle of the LED array face in the horizontal direction. With pitch angle The azimuth angle of the LED array in the vertical direction With pitch angle

[0126] Step S1022: Set the receiver parameters, including the azimuth angle of the receiver normal. With pitch angle Area A of the receiving end R The visible field of view Ψ of the receiving end FoV , Translational motion direction angle of the receiving end With pitch angle and the magnitude of the velocity v R (t) Rotational azimuth velocity of the receiving end With pitch angular velocity

[0127] Step S1023: Set distance parameters, including the first row and first column of LED units L of the LED array. 11 Distance D from the receiver 11 ;

[0128] Step S1024: Set the blocking effect parameters, including the probability p that the line-of-sight component is blocked. blpckage .

[0129] Step S103: Set frequency band related parameters, including the single-cluster propagation ratio η. SB The probability p that the propagation component is scattered by particles in the environment particleThe proportion α of diffuse reflection of light signals on materials in the environment n Extended parameter σ of the object reflection cluster RE Extended parameter σ of particle scattering cluster PS Particle extinction coefficient k e Rayleigh scattering coefficient k of particles sr Particle Mie scattering coefficient k sm In the ultraviolet band, due to the significant path loss, only single-cluster propagation is considered, so the proportion of single-cluster propagation is set to 1. The effects of particle scattering and extinction in the ultraviolet band must be taken into account; therefore, the particle scattering probability p... particle、 Particle extinction coefficient k e Rayleigh scattering coefficient k of particles sr With particle Mie scattering coefficient k sm Extended parameter σ of particle scattering cluster Ps All are non-zero; in the infrared and visible light bands, dual-cluster propagation is usually considered, and particle scattering and extinction effects do not need to be considered, p particle With k e k sr k sm σ PS All are set to zero; furthermore, as the frequency band increases, the light signal is more prone to diffuse reflection, and the proportion α of the light signal diffusely reflected on materials in the environment... n The extended parameter σ of the object's reflection cluster RE Increase.

[0130] Step S2 generates the matrix of the birth and death process of the object reflection clusters on the transmitting end array, the random number matrix controlling the existence of the direct component, and the random number matrix for classifying the propagation components.

[0131] Specifically, in this embodiment, step S2 includes:

[0132] Step S201: Generate the matrix of the birth and death process of the object reflection clusters on the transmitting end array. Specific steps include:

[0133] Step S2011: Calculate LED unit L 11 The number of clusters N observed at the initial moment c0 The expression is:

[0134]

[0135] In the formula, λ B With λ D These represent the birth rate and death rate of the cluster, respectively.

[0136] Step S2012, using LED unit L 11 Based on this, the first column of LED units is generated. For the visibility matrix of clusters, where column evolution is performed in the horizontal direction, the clusters are at a spacing of The probability of survival at a distance of:

[0137]

[0138] In the formula, Array-related factors are specific to certain scenarios;

[0139] The number of newly generated clusters follows a Poisson distribution with a mean of:

[0140]

[0141] Step S2013: Using the first column of LED units generated in step S2012 Based on this, a visibility matrix for each column of LED units to the cluster is generated, wherein column evolution is performed in the vertical direction, and the clusters are spaced at intervals of [missing information]. The probability of survival at a distance of:

[0142]

[0143] The number of newly generated clusters follows a Poisson distribution with a mean of:

[0144]

[0145] Step S2014: Generate the final object reflection cluster birth and death process matrix, which is a matrix of size M. I ×M J ×N c，total The matrix, where N is the total number of object reflection clusters. c，total equals N c0 The sum of the number of clusters and the number of newly generated clusters.

[0146] Step S202: Calculate the probability p of the direct component existing. LoS =(1-p blockage )·(1-p particle Based on this probability, a 0 / 1 random number matrix of size M is generated to control the existence of the direct component. I ×M J According to p particle Generate M n A random number (M) is used to classify whether the propagated component after reflection from an object is scattered again before reaching the receiver. n This represents the number of scatterers within the object's reflection cluster.

[0147] Step S3: Initialize the object reflection cluster, particle scattering cluster, and intra-cluster scatterers.

[0148] Specifically, in this embodiment, step S3 includes:

[0149] Step S301: Randomly generate the initial position of the object reflection cluster. The initial position of the cluster is determined by the azimuth angle, pitch angle, and distance parameters. This step specifically includes:

[0150] Step S3011: Randomly generate N c，total The angular parameters of each object reflection cluster are all modeled as following a tangled normal distribution, such as the pitch departure angle of the object reflection cluster on the transmitter side. Angle of departure from azimuth It can be generated from the following assumptions:

[0151]

[0152]

[0153] In the formula, Let be the variances of the pitch departure angle and azimuth departure angle of the object's reflection cluster, respectively. and These are the mean values ​​of the pitch departure angle and azimuth departure angle of the object's reflective cluster, respectively; similarly, N is generated. c，total ×(1-η SB ) Angular parameters of the object reflection clusters at the receiving end;

[0154] Step S3012: Randomly generate the initial distance L between the object reflection cluster and the LED unit. 11 distance and Furthermore, it follows a non-negative exponential distribution;

[0155] Step S302: Calculate the equivalent normal direction and equivalent specular reflection direction of each object reflection cluster based on geometric relationships; for a single object reflection, the equivalent normal points from the cluster center to L. 11 The ray reaching the receiving end and perpendicular to the ray, its equivalent specular reflection direction vector is intersected with the cluster center, L 11 And the receiving end is in the same plane, and the angle between it and the equivalent normal is equal to the distance from the cluster center to L. 11 The angle between the vector and the equivalent normal; in the case of double object reflection, the equivalent normal of the cluster on the emitting end points from the cluster center to L. 11 The ray reaching the cluster at the receiving end and perpendicular to the ray, its equivalent specular reflection direction vector is perpendicular to the cluster center, L 11 The clusters on the receiving end side are located in the same plane, and the angle between them and the equivalent normal is equal to the distance from the cluster center to L. 11The angle between the vector and the equivalent normal, the equivalent normal of the receiver-side cluster points from the cluster center to the ray from the transmitter-side cluster to the receiver and is perpendicular to the ray, its equivalent mirror reflection direction vector is in the same plane as the cluster center, the transmitter-side cluster and Rx, and the angle between it and the equivalent normal is equal to the angle between the vector from the cluster center to the transmitter-side cluster and the equivalent normal.

[0156] Step S303: Generate a particle scattering cluster characterizing the particle scattering effect of ultraviolet light signal on the receiving end side. The azimuth and elevation angles of the ray from the receiving end to the center of the particle scattering cluster are consistent with the normal direction of the receiving end. The distance between the center of the particle scattering cluster and the receiving end is set to a constant.

[0157] Step S304: Randomly generate the coordinates of each cluster scatterer in the global coordinate system. This step specifically includes:

[0158] Step S3041: Randomly generate the coordinates [x′, y′, z′] of the scatterer within each cluster in a local coordinate system with the cluster center as the origin. T Furthermore, it follows a three-dimensional ellipsoidal Gaussian distribution, expressed as:

[0159]

[0160] In the formula, σ DS σ AS σ ES These represent intra-cluster time delay spread, angular spread, and pitch spread, respectively. When generating object reflection clusters and particle scattering clusters, different cluster spread parameters are substituted in.

[0161] Step S3042: Obtain the coordinates [x, y, z] of each scatterer in the global coordinate system through coordinate transformation. T The expression is:

[0162]

[0163] In the formula, These represent the average distance, azimuth, and elevation angle of a cluster, respectively.

[0164] Step S4: Update the model parameters that vary with space and time.

[0165] Specifically, in this embodiment, step S4 includes:

[0166] Step S401: Based on the geometric relationship and the set motion velocity of the object reflection cluster, the motion and rotation velocity of the receiver, update the coordinates of the scatterer and the receiver in the global coordinate system at each moment, and calculate L. ijIn the global coordinate system, note that the position of the scatterer in the particle scattering cluster changes synchronously with the movement and rotation of the receiver. The ray direction from the receiver to the center of the particle scattering cluster is always consistent with the normal direction of the receiver, and the distance from the center of the particle scattering cluster to the receiver remains unchanged.

[0167] Step S402: Update and calculate the angle parameters of each propagation ray in the local coordinate system of each LED unit. Specific steps include:

[0168] Step S4021: Take the cell L containing the i-th row and j-th column of the LED array as an example. ij With the origin as the reference point, the normal direction of the LED array is x′. ij The axis and the vertical direction of the LED array are y′. ij The axis and the horizontal direction of the LED array are z′ ij Axis establishes LED unit L ij The local coordinate system;

[0169] Step S4022: First, the Cartesian coordinates of each scatterer obtained in step S3042 in the global coordinate system are rotated to obtain the LED unit L. 11 The Cartesian coordinates of the local coordinate system are then transformed to obtain the LED element L. ij The Cartesian coordinates of the local coordinate system are used to finally determine the LED element L. ij Converting the Cartesian coordinates of the local coordinate system to spherical coordinates, we obtain the coordinates of each propagating ray in the LED unit L. ij Pitch departure angle and azimuth departure angle in the local coordinate system, including the direct path in L ij Pitch departure angle in local coordinate system Angle of departure from azimuth From L ij The ray reaching the q-th scatterer within the particle scattering cluster at L ij Pitch departure angle in local coordinate system Angle of departure from azimuth From L ij The ray from the m1 (m2)th scatterer within the nth object reflection cluster at the emitting end is at L ij Pitch departure angle in local coordinate system Angle of departure from azimuth

[0170] Step S403: Calculate the angle parameters of each propagating ray based on the updated global coordinates of each scatterer and receiver in step S401. Specific steps include:

[0171] Step S4031: Based on the propagation component classification 0 / 1 random number generated in step S202, determine whether the ray in the single object reflection cluster reaches the receiving end only after a single reflection. The ray directly reaches the receiving end after passing through the m1 scatterer in the nth single object reflection cluster, and after passing through the m2 scatterer in the nth single object reflection cluster, it is scattered by particles again before reaching the receiving end.

[0172] Step S4032: Obtain the normalized transmission vector according to the coordinate method, including L ij Normalized direction vector to the receiver L ij Normalized direction vector to the q-th scatterer within the particle scattering cluster Normalized direction vector from the q-th scatterer in the particle scattering cluster to the receiver L ij The normalized direction vector of the m1(m2)th scatterer within the nth object reflection cluster at the transmitter side The normalized direction vector from the m1(m2)th scatterer within the nth object reflection cluster at the transmitter to the receiver. The normalized direction vector from the m1-th scatterer within the nth object reflection cluster at the transmitter side to the m1-th scatterer within the nth object reflection cluster at the receiver side. The normalized direction vector from the m2-th scatterer within the n-th object reflection cluster at the emitter side to the q-th scatterer within the particle scattering cluster.

[0173] Step S4033: Update and calculate the included angle parameters of each propagation component according to the law of cosines, including... Angle with the direction of the receiver's normal and The included angle Angle with the direction of the receiver's normal The angle between the equivalent normal direction of the nth object reflection cluster on the transmitter side and the target surface. The angle between the equivalent normal direction and the equivalent specular reflection direction of the nth object reflection cluster on the transmitter side and Angle with the direction of the receiver's normal The angle between the equivalent normal direction and the equivalent specular reflection direction of the nth object reflection cluster on the transmitter side and and The included angle

[0174] Step S404: Based on the updated scatterers and L from step S401 ij The global coordinates of the receiving end and the coordinate method are used to update and calculate the propagation distance parameters of each propagating ray at each moment, including L. ijDistance D to the receiver ij (t), L ij Distance to the q-th scatterer within the particle scattering cluster The distance from the q-th scatterer within the particle scattering cluster to the receiver. L ij Distance to the m1(m2)th scatterer within the nth object reflection cluster on the transmitter side The distance from the m1 (m2)th scatterer within the nth object reflection cluster on the transmitter side to the receiver. The distance from the m1-th scatterer within the n-th object reflection cluster on the transmitter side to the m1-th scatterer within the n-th object reflection cluster on the receiver side. The distance from the m2-th scatterer within the n-th object reflection cluster on the emitter side to the q-th scatterer within the particle scattering cluster.

[0175] Step S5: Calculate the light source radiation intensity, object reflection power distribution, particle scattering power distribution, and equivalent reflection coefficient related to wavelength range.

[0176] Specifically, in this embodiment, step S5 includes:

[0177] Step S501: Calculate the light source radiation intensity in the direction corresponding to the propagating ray, expressed as:

[0178]

[0179] In the formula, α is the mode number of the Lambertian radiation mode; substitute the angle parameters calculated in step S4022 into the above formula to calculate the light source radiation intensity corresponding to each propagation component respectively;

[0180] Step S502: Calculate the power distribution of the propagating ray after reflection by the object based on Phong's reflection model. The expression is:

[0181]

[0182] In the formula, m sn Here is the directional parameter of the specular reflection component; Substitute the angle parameter between the propagation ray and the equivalent normal of the object reflection cluster and the equivalent specular reflection direction calculated in step S4033 into the above formula to calculate the power radiated per unit solid angle in the propagation direction of the propagation component after object reflection.

[0183] Step S503: Calculate the power distribution of the propagating ray after particle scattering based on the particle scattering phase function. The expression is:

[0184]

[0185] In the formula, k s The scattering coefficient is equal to the Rayleigh scattering coefficient k of the particle. sr With particle Mie scattering coefficient k sm The sum of P r (θ PS ) and P m (θ PS ) are the Rayleigh scattering phase function and the Mie scattering phase function, respectively, where,

[0186] P r (θ PS The expression for ) is:

[0187]

[0188] In the formula, γ is a parameter of the Rayleigh scattering model, which is determined by the depolarization factor;

[0189] P m (θ PS The expression for ) is:

[0190]

[0191] In the formula, g and f are Mie scattering model parameters related to the light wavelength; the angle parameters calculated in step S4033 are used. and Substituting into the particle scattering phase function expression, the power radiated per unit solid angle in the propagation direction of the propagation component after particle scattering is calculated respectively.

[0192] Step S504: Calculate the equivalent reflection coefficient related to the wavelength range, expressed as:

[0193]

[0194] In the formula, Φ ij (λ) represents the LED unit L ij Radiative power spectral density as a function of wavelength, ρ n (λ) represents the reflectivity of the nth object's reflective cluster as a function of wavelength, and [λ1, λ2] represents the wavelength range of the light emitted by the LED, which is set according to the specific light signal used.

[0195] Specifically, in this embodiment, step S6 includes:

[0196] Step S601: Calculate the channel impulse response of the direct propagation component. Specific steps include:

[0197] Step S6011: Calculate the power of the direct propagation component of the ray, expressed as:

[0198]

[0199] In indoor scenes, within the infrared and visible light frequency bands, the particle extinction effect does not need to be considered, and k is set accordingly. e When = 0, the model simplifies to a model that supports both infrared and visible light, and the particle extinction decay is 1;

[0200] Step S6012: Calculate the propagation delay of the direct propagation component, expressed as:

[0201]

[0202] In the formula, c l The speed of light;

[0203] Step S6013: Generate the channel impulse response of the direct component in each sub-channel based on the parameters calculated in steps S6011 and S6012, expressed as:

[0204]

[0205] Step S602: Calculate the channel impulse response of the non-direct propagation component. Specific steps include:

[0206] Step S6021, calculate from L ij The power of the propagating component of the emitted ray that reaches the receiver only after being scattered by particles is expressed as:

[0207]

[0208] V in the formula q，eff Let V be the equivalent volume of each scatterer in the particle scattering cluster, and V be the equivalent volume of the particle scattering cluster. c，eff Correlation, calculated as V q，eff =V c，eff / Q PS Q PS G(ψ) represents the number of scatterers in the particle scattering cluster. R ) and T(ψ R ) represent the gain of the optical focusing lens and the gain of the optical filter, respectively, V(ψ) R ) is the visible area function, where,

[0209] V(ψ R The expression for ) is:

[0210]

[0211] Step S6022: Calculate from L ij The time delay of the propagating component of the emitted ray that reaches the receiver only after being scattered by particles is expressed as:

[0212]

[0213] Step S6023, calculate from L ij The power of the propagating component of the emitted ray that reaches the receiver only after being reflected by an object, where,

[0214] In the case of a single reflection, the expression is:

[0215]

[0216] For the case of double object reflection, the channel is characterized by two clusters located at the transmitting and receiving ends respectively. The calculation of its ray power is similar to that of single reflection, but with the addition of power loss from the scatterer at the transmitting end to the scatterer at the receiving end.

[0217] Step S6024: Calculate from L ij The power of the propagating component of the emitted ray that reaches the receiver only after being reflected by an object, where,

[0218] In the case of a single reflection, the expression is:

[0219]

[0220] In the case of double reflection, the expression is:

[0221]

[0222] Step S6025: Calculate from L ij The power of the propagating component of the emitted ray, after being reflected by an object and scattered by particles again, is expressed as:

[0223]

[0224] Wherein, the signal passes through a random M within each object reflection cluster. n ·p particle Each scatterer undergoes particle scattering again. Based on the propagation component classification 0 / 1 random number generated in step S202, it is determined whether the rays in the object reflection cluster have undergone single object reflection and particle scattering again to reach the receiving end.

[0225] Step S6026: Calculate from L ij The propagation time delay of the component that is reflected by an object and then scattered by particles is expressed as:

[0226]

[0227] Step S6027: Generate the channel impulse response of the direct component in each sub-channel based on the parameters calculated in steps S6021 to S6026, the expression of which is:

[0228]

[0229] In the formula, N ij (t) represents the LED unit L ij The number of clusters of the sub-channels at time t at the receiving end; where, in indoor scenes, in the infrared and visible light bands, particle scattering and extinction effects do not need to be considered, and p is set. particle =0, k e When =0, the model is simplified to a model that supports infrared and visible light, with only the non-direct component that reaches the receiver after being reflected by the object, and the particle extinction attenuation of the non-direct component calculated in step S6023 is 1.

[0230] Step S603: Determine whether the non-direct component corresponding to the object reflection cluster exists based on the birth and death matrix generated in step S201, and set the contribution of the invisible link to the channel impulse response to zero.

[0231] Step S604: Determine whether the direct component exists in each sub-channel based on the random number matrix generated in step S202 that controls the existence of the direct component, and obtain the final channel impulse response.

[0232] Step S6: Calculate the impulse response of each sub-channel, determine whether the direct component of the sub-channel exists and whether the indirect component of the object reflection exists, and obtain the final channel impulse response.

[0233] The general geometric random channel modeling method for indoor optical wireless communication proposed in the embodiments of this application integrates the common characteristics of optical wireless communication frequency bands in typical indoor scenarios with the typical characteristics of infrared, visible, and ultraviolet light frequency bands. By setting the corresponding parameters, the established model can be simplified into an optical wireless channel model for the corresponding band, which can be flexibly used for simulation and performance evaluation of 6G optical wireless communication systems.

[0234] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0235] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0236] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

Claims

1. A general geometric random channel modeling method for indoor optical wireless communication, characterized in that, Includes the following steps: Step S1: Establish an indoor optical wireless communication channel simulation scenario, and set the simulation scenario layout and frequency band parameters, including the proportion of single-cluster propagation. The probability that the propagation component is scattered by particulate matter in the environment. The proportion of light signals diffusely reflected by materials in the environment Extended parameters of object reflection clusters Extended parameters of particle scattering clusters Particle extinction coefficient Rayleigh scattering coefficient of particles Mie scattering coefficient ; Step S2: Generate the object reflection cluster birth and death process matrix of the transmitting end array, the random number matrix controlling the existence of the direct component, and the random number matrix classifying the propagation components; Step S3: Initialize the object reflection cluster, particle scattering cluster, and intra-cluster scatterers; Step S4: Update the model parameters that vary with space and time; Step S5: Calculate the light source radiation intensity, object reflected power distribution, particle scattered power distribution, and equivalent reflection coefficient related to wavelength range; Step S5 further includes: Step S501: Calculate the light source radiation intensity in the direction corresponding to the propagating ray, expressed as: in, The mode number of the Lambertian radiation mode; the light source radiation intensity corresponding to each propagation component is calculated based on the angle parameters of each propagation ray in the local coordinate system of each LED unit; Step S502: Calculate the power distribution of the propagating ray after reflection by the object based on Phong's reflection model. The expression is: in, Here are the directional parameters of the specular reflection component; based on the angle between the equivalent normal of the propagating ray and the object's reflection cluster and the equivalent specular reflection direction, the power radiated per unit solid angle in the propagation direction of the propagating component after reflection by the object is calculated respectively. Step S503: Calculate the power distribution of the propagating ray after particle scattering based on the particle scattering phase function. The expression is: in, The scattering coefficient is equal to the Rayleigh scattering coefficient of the particle. With particle Mie scattering coefficient The sum of and These are the Rayleigh scattering phase function and the Mie scattering phase function, respectively, where, The expression is: in, These are parameters of the Rayleigh scattering model, determined by the depolarization factor; The expression is: in, and The parameters of the Mie scattering model are related to the light wavelength; based on the angle parameters of each propagation component, the LED array unit... to the particle scattering cluster The normalized direction vector of the i-th scatterer and the i-th particle scattering cluster The angle between the normalized direction vectors of the scatterers and the receiver. , and the first on the transmitting end side The m2th scatterer within the m2th object reflection cluster becomes the m2th scatterer within the particle scattering cluster. The normalized direction vector of the i-th scatterer and the i-th particle scattering cluster The angle between the normalized direction vectors of the scatterers and the receiver. The power radiated per unit solid angle in the propagation direction of the propagation component after particle scattering was calculated respectively. Step S504: Calculate the equivalent reflection coefficient related to the wavelength range, expressed as: in, LED unit Radiative power spectral density as a function of wavelength For the first The reflectivity of an object's reflective cluster as a function of wavelength. The wavelength range of the light emitted by an LED lamp; Step S6: Calculate the impulse response of each sub-channel, determine whether the direct component of the sub-channel exists and whether the indirect component of the object reflection exists, and obtain the final channel impulse response.

2. The method according to claim 1, characterized in that, Step S1 further includes: Step S101: Establish an indoor optical wireless communication channel simulation scenario. The indoor optical wireless communication channel simulation scenario includes an LED array as the transmitter and a photodetector as the receiver. The ray from the first row and first column of LED units at the transmitter to the receiver is defined as... The axis, and the plane perpendicular to it, are used as... Establish a global coordinate system. Step S102: Set the physical environment parameters of the simulation scene layout, including transmitter parameters, receiver parameters, distance parameters, and blocking effect parameters; Step S103: Set frequency band parameters.

3. The method according to claim 2, characterized in that, Step S102 further includes: Step S1021: Set the transmitter parameters, including the direction parameters of the LED array and the number of LED units in the horizontal direction of the LED array. and unit spacing The number of LED units in the vertical direction of the LED array and unit spacing The orientation parameters of the LED array include the azimuth angle of the LED array face in the horizontal direction. With pitch angle azimuth angle of LED array in the vertical direction With pitch angle ; Step S1022: Set the receiver parameters, including the azimuth angle of the receiver normal. With pitch angle Area of ​​the receiving end The visible angle of the receiving end , Translational motion direction angle of the receiving end With pitch angle and speed Angular velocity of rotation at the receiving end With pitch angular velocity ; Step S1023: Set distance parameters, including the first row and first column of LED units in the LED array. Distance from the receiver ; Step S1024: Set the blocking effect parameters, including the probability that the line-of-sight component is blocked. .

4. The method according to claim 3, characterized in that, Step S2 further includes: Step S201, generating the object reflection cluster birth and death process matrix of the transmitting end array, specifically including: Step S2011, calculate the LED unit The number of clusters seen at the initial moment The expression is: in, and These represent the birth rate and death rate of the cluster, respectively. Step S2012, using the LED unit Based on this, the first column of LED units is generated. For the visibility matrix of clusters, where column evolution is performed in the horizontal direction, the clusters are at a spacing of The probability of survival at a distance of: in, For array-related factors that are relevant to specific scenarios; The number of newly generated clusters follows a Poisson distribution with a mean of: Step S2013, using the first column of LED units generated in step S2012 Based on this, a visibility matrix for each column of LED units to the cluster is generated, wherein column evolution is performed in the vertical direction, and the clusters are spaced at intervals of [missing information]. The probability of survival at a distance of: The number of newly generated clusters follows a Poisson distribution with a mean of: Step S2014: Generate the final object reflection cluster birth and death process matrix of the transmitting end array, which is a matrix of size [missing information]. The matrix, where the total number of object reflection clusters is... equal The sum of the number of newly generated clusters; Step S202: Calculate the probability of the existence of the direct component. A 0 / 1 random number matrix of size is generated based on the probability of the presence of the direct component to control the existence of the direct component. ;according to generate A random number (0 / 1) is used to classify whether the propagated component after reflection from an object is scattered again before reaching the receiver. This represents the number of scatterers within the object's reflection cluster.

5. The method according to claim 1, characterized in that, Step S3 further includes: Step S301: Randomly generate the initial position of the object reflection cluster. The initial position of the cluster is determined by the azimuth angle, pitch angle, and distance parameters, specifically including: Step S3011, randomly generate The angular parameters of each object's reflection cluster are all modeled as following a tangled normal distribution, generating... The angular parameters of the object reflection cluster at each receiver; Step S3012: Randomly generate the initial distance between the object reflection cluster and the LED unit. distance and And it follows a non-negative exponential distribution; Step S302: Calculate the equivalent normal direction and equivalent specular reflection direction of each object reflection cluster based on geometric relationships; for a single object reflection, the equivalent normal points from the cluster center to... The ray reaching the receiving end and perpendicular to the ray, the equivalent specular reflection direction vector is perpendicular to the cluster center, And the receiving end is in the same plane, and the angle between it and the equivalent normal is equal to the angle from the cluster center to the equivalent normal. The angle between the vector and the equivalent normal; in the case of double object reflection, the equivalent normal of the cluster on the emitting end points from the cluster center to... The ray reaching the cluster at the receiving end and perpendicular to the ray, its equivalent specular reflection direction vector is perpendicular to the cluster center. The clusters on the receiving end side are located in the same plane, and the angle between the cluster center and the equivalent normal is equal to the angle from the cluster center to the equivalent normal. The angle between the vector and the equivalent normal, the equivalent normal of the receiver-side cluster points from the cluster center to the ray from the transmitter-side cluster to the receiver and is perpendicular to the ray, its equivalent mirror reflection direction vector is in the same plane as the cluster center, the transmitter-side cluster and Rx, and the angle between it and the equivalent normal is equal to the angle between the vector from the cluster center to the transmitter-side cluster and the equivalent normal. Step S303: Generate a particle scattering cluster characterizing the particle scattering effect of ultraviolet light signal on the receiving end side. The azimuth and elevation angles of the ray from the receiving end to the center of the particle scattering cluster are consistent with the normal direction of the receiving end. The distance from the center of the particle scattering cluster to the receiving end is set to a constant. Step S304: Randomly generate the coordinates of each cluster scatterer in the global coordinate system, specifically including: Step S3041: Randomly generate the coordinates of the scatterers within each cluster in a local coordinate system with the cluster center as the origin. Furthermore, it follows a three-dimensional ellipsoidal Gaussian distribution, expressed as: in, , These represent intra-cluster time delay spread, angle spread, and pitch spread, respectively. When generating object reflection clusters and particle scattering clusters, different cluster spread parameters are substituted in. Step S3042: Obtain the coordinates of each scatterer in the global coordinate system through coordinate transformation. The expression is: in, , , These represent the average distance, azimuth, and elevation angle of a cluster, respectively.

6. The method according to claim 5, characterized in that, Step S4 further includes: Step S401: Based on the geometric relationships and the set motion speed of the object reflection cluster, the motion and rotation speed of the receiver, update the coordinates of the scatterer and the receiver in the global coordinate system at each moment, and calculate... Coordinates in the global coordinate system; Step S402, update and calculate the angle parameters of each propagation ray in the local coordinate system of each LED unit. Specific steps include: Step S4021, using the LED array's first... line, number The cell where the column is located With the origin as the normal direction of the LED array, The vertical direction of the axis and the LED array is The horizontal direction of the axis and LED array is Axis establishes LED unit The local coordinate system; Step S4022: The Cartesian coordinates of each scatterer obtained in step S3042 in the global coordinate system are first transformed by rotation to obtain the LED unit. The Cartesian coordinates of the local coordinate system are then transformed to obtain the LED unit. The Cartesian coordinates of the local coordinate system are used to finally determine the LED unit. Converting the Cartesian coordinates of the local coordinate system to spherical coordinates, we can obtain the coordinates of each propagating ray within the LED unit. Pitch departure angle and azimuth departure angle in the local coordinate system, including the direct path. Pitch departure angle in local coordinate system Angle of departure from azimuth ,from to the particle scattering cluster The rays from the scatterer Pitch departure angle in local coordinate system Angle of departure from azimuth ,from To the transmitting end side The rays of the scattering body within the reflection cluster of an object are... Pitch departure angle in local coordinate system Angle of departure from azimuth ; Step S403 involves updating and calculating the angle parameters of each propagating ray based on the updated global coordinates of each scatterer and receiver in step S401. Specific steps include: Step S4031: Based on the propagation component classification 0 / 1 random number generated in step S202, determine whether the rays in the single object reflection cluster reach the receiving end only after a single reflection. Step S4032: Obtain the normalized transmission vector according to the coordinate method, including Normalized direction vector to the receiver , to the particle scattering cluster Normalized direction vector of each scatterer The first particle scattering cluster Normalized direction vectors from each scatterer to the receiver , To the transmitting end side Normalized direction vector of scatterers within an object reflection cluster , the first on the transmitting end side Normalized direction vector from the scatterer within an object reflection cluster to the receiver. , the first on the transmitting end side Within the reflection cluster of the nth object The scatterer reaches the receiver side. Within the reflection cluster of the nth object Normalized direction vector of each scatterer , the first on the transmitting end side Within the reflection cluster of the nth object The scatterer enters the particle scattering cluster. Normalized direction vector of each scatterer ; Step S4033: Update the angle parameters of each propagation component according to the law of cosines, including... Angle with the direction of the receiver's normal , and The included angle , Angle with the direction of the receiver's normal , With the transmitter side The angle between the equivalent normal directions of the reflection cluster of an object and the angle between the reflection cluster and the reflection direction of the object. , With the transmitter side The angle between the equivalent normal direction of the reflection cluster of an object and the equivalent specular reflection direction and , Angle with the direction of the receiver's normal , With the transmitter side The angle between the equivalent normal direction of the reflection cluster of an object and the equivalent specular reflection direction and , and The included angle ; Step S404, based on the updated scatterers in step S401, The global coordinates of the receiving end and the coordinate method are used to update and calculate the propagation distance parameters of each propagating ray at each moment, including... Distance to the receiver , to the particle scattering cluster Distance of each scatterer The first particle scattering cluster Distance from each scatterer to the receiver , To the transmitting end side Distance of scatterers within an object's reflection cluster , the first on the transmitting end side The distance from the scatterer within the reflection cluster of an object to the receiver. , the first on the transmitting end side Within the reflection cluster of the nth object The scatterer reaches the receiver side. Within the reflection cluster of the nth object Distance of each scatterer , the first on the transmitting end side Within the reflection cluster of the nth object The scatterer enters the particle scattering cluster. Distance of each scatterer .

7. The method according to claim 6, characterized in that, Step S6 further includes: Step S601, calculate the channel impulse response of the direct propagation component, specifically including: Step S6011: Calculate the power of the direct propagation component of the ray, expressed as: Among them, in the infrared and visible light frequency bands of indoor scenes, [the following settings are provided]. At that time, the model was simplified to support both infrared and visible light, and the particle extinction decay was 1. Step S6012, calculate the propagation delay of the direct propagation component, the expression is: in, The speed of light; Step S6013: Generate the channel impulse response of the direct component in each sub-channel based on the parameters calculated in steps S6011 and S6012, expressed as: Step S602, calculate the channel impulse response of the non-direct propagation component, specifically including: Step S6021, calculate from The power of the propagating component of the emitted ray that reaches the receiver only after being scattered by particles is expressed as: in, The equivalent volume of each scatterer in the particle scattering cluster, and the equivalent volume of the particle scattering cluster. Related, calculated as , The number of scatterers in the particle scattering cluster; and These are the gains of the optical focusing lens and the optical filter, respectively. For visible field functions, The expression is: Step S6022, calculate from The time delay of the propagating component of the emitted ray that reaches the receiver only after being scattered by particles is expressed as: Step S6023, calculate from The power of the propagating component of the emitted ray that reaches the receiver only after being reflected by an object, in the case of a single reflection, is expressed as: In the case of double object reflection, the channel is characterized by two clusters located at the transmitting and receiving ends respectively. Compared with the case of single reflection, the calculation of ray power increases the power loss from the scatterer at the transmitting end to the scatterer at the receiving end. Step S6024, calculate from The power of the propagating component of the emitted ray that reaches the receiver only after being reflected by an object, in the case of a single reflection, is expressed as: In the case of double reflection, the expression is: Step S6025, calculate from The power of the propagating component of the emitted ray, after being reflected by an object and scattered by particles again, is expressed as: The signal passes through random reflection clusters within each object. Each scatterer undergoes particle scattering again. Based on the propagation component classification 0 / 1 random number generated in step S202, it is determined whether the rays in the object reflection cluster have undergone single object reflection and particle scattering again to reach the receiving end. Step S6026, calculate from The propagation time delay of the component that is reflected by an object and then scattered by particles is expressed as: Step S6027: Generate the channel impulse response of the direct component in each sub-channel based on the parameters calculated in steps S6021 to S6026, the expression of which is: in, Indicates LED unit Sub-channels to the receiving end Cluster number at any given time; setting the infrared and visible light frequency bands in indoor scenes. , At that time, the model is simplified to support infrared and visible light, with only the non-direct component that reaches the receiver after being reflected by the object, and the particle extinction attenuation of the non-direct component calculated in step S6023 is 1. Step S603: Determine whether the non-direct component corresponding to the object reflection cluster exists based on the birth and death matrix generated in step S201, and set the contribution of the invisible link to the channel impulse response to zero. Step S604: Determine whether the direct component exists in each sub-channel based on the random number matrix generated in step S202 that controls the existence of the direct component, and obtain the final channel impulse response.

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